1. Field of the Invention
The present invention relates to a thermal power plant and more particularly to a fossil fuel combustion thermal power plant including a carbon dioxide separation and capture apparatus, a steam turbine and a control method for a thermal power plant.
2. Description of Related Art
As a fossil fuel combustion thermal power system including a carbon dioxide separation and capture apparatus, for example, there is a system including an apparatus (PCC: post combustion CO2 capture) for separating and capturing carbon dioxide from combustion exhaust gas of a coal combustion boiler using a CO2 absorbing liquid. As a conventional technology of this system, there is a system including a steam turbine having a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine, a boiler for generating steam for driving these turbines, a CO2 absorber for absorbing and removing CO2 from combustion gas of the boiler using the CO2 absorbing liquid, a desorber for desorbing the CO2 absorbing liquid that has absorbed CO2, and a reboiler for feeding a heating source for separating CO2 from the absorbing liquid to the desorber.
Generally, a conventional carbon dioxide separation and capture apparatus for capturing CO2 from exhaust gas of the boiler drives an absorbing liquid circulation pump to circulate the CO2 absorbing liquid between the absorber and the desorber, absorbs CO2 contained in boiler exhaust gas into the absorbing liquid by the absorber, and separates and captures CO2 absorbed in the absorbing liquid by the desorber. For the heating source for separating CO2 from the absorbing liquid by the desorber, steam fed from the reboiler is used and for the heating source of the reboiler, a part of steam taken out from the high-pressure and intermediate-pressure turbines is used (refer to Patent document 1).
{Patent document 1} Japanese Patent No. 4274846